A070061 Least number of fecundity n (A070562).

0, 5, 25, 19, 23, 18, 9, 7, 4, 2, 1, 282, 1529, 1586, 1397, 898, 658, 538, 477, 529, 736, 586, 397, 366, 294, 246, 243, 187, 3237326, 3677393, 3586673, 3553787, 3515987, 22572473, 518376965, 516675965, 516963965, 41883474553, 41881554553, 41863638649, 35632297938395

Offset: 0

Author

Lekraj Beedassy, May 06 2002

Keywords

• base
• hard
• nonn

Comments

a(41) > 2.75*10^14. - Giovanni Resta, Jun 04 2013

Examples

			a(9)=2 since we have the 9-step chain 2 -> 4 -> 8 -> 16 -> 22 -> 26 -> 38 -> 62 -> 74 -> 102.
		

References

• P. Tougne, Jeux Mathematiques column, Pour La Science (French edition of "Scientific American"), Vol. 82, Aug. 1984, Prob. 6, pp. 101, 104.

Crossrefs

Cf. A070562, A070257, A003001.

Programs

Mathematica

f[n_] := Length@ FixedPointList[ # + Times @@ IntegerDigits@# &, n] - 2; t = Table[0, {50}]; k = 1; While[k < 2300000001, a = f@k; If[ t[[a + 1]] == 0, t[[a + 1]] = k; Print[{k, a}]]; k++ ]; t (* Robert G. Wilson v, Jun 27 2010 *)

Extensions

Corrected and extended by Jason Earls, May 26 2002

a(34)-a(36) from Robert G. Wilson v, Jun 27 2010

a(37)-a(40) from Giovanni Resta, Jun 04 2013